1. Field of the Invention
This invention relates to so-called quick connect/disconnect couplings. More particularly, this invention relates to a quick connect/disconnect coupling which includes a positive locking means which prevents inadvertent disconnection of the coupling.
Couplings of this type, in various sizes, are commonly used as connections for fluid conduits used for transferring liquids in bulk from one location to another. Quick connect/disconnect couplings, or QCD couplings, are in widespread use for conduits such as pipes and hoses commonly having internal diameters of from about 1.25 cm to at least 20 cm; in theory there is no upper size limitation. The QCD coupling comprises two essential parts, which are a coupler and an adapter. The coupler is usually attached to, or mounted into the end of, a flexible conduit, such as a hose. The adapter is usually mounted onto a relatively fixed conduit, such as the end of a metal pipe, or a manifold attached to a storage tank or the like. These arrangements can be reversed, so that for example the adapter can also be mounted into the end of a flexible conduit such as a hose. Generally the two conduits are of about the same size in terms of internal bore; it is also known to construct QCD couplers to join two conduits which are of different sizes.
The male adapter includes an arcuate groove around its outer substantially cylindrical face adjacent its sealing end, which is inserted into the female coupler bore. The coupler also includes at least two locking levers, which include cam means extending through slots into the bore of the coupler. To connect the QCD coupling, the adapter is entered into the bore of the coupler with the levers placed in the xe2x80x9copenxe2x80x9d position. The levers are then moved from the xe2x80x9copenxe2x80x9d position to the xe2x80x9clockedxe2x80x9d position, thus forcing the cams into engagement with the arcuate groove. Movement of the levers both locks the adapter into the coupler, and urges the adapter into engagement with a seal bedded onto a suitably located face in the coupler, to provide a positively locked and liquid tight connection between the two conduits. The seal is commonly fabricated from an elastomeric material. The QCD coupling is separated by moving the levers from the xe2x80x9clockedxe2x80x9d position to the xe2x80x9copenxe2x80x9d position, thus freeing the adapter from the coupler and permitting separation of the two parts of the coupling.
2. Discussion of Related Art
Although QCD couplings of this general type have been in commercial use for many years, they still suffer from one important disadvantage. Even though some force is required to move the locking levers from the xe2x80x9clockedxe2x80x9d to the xe2x80x9copenxe2x80x9d position, especially if fluid carrying conduits joined by a coupling are under pressure, in the absence of any other protective device, the risk exists that one, or more, of the levers may be inadvertently moved from the xe2x80x9clockedxe2x80x9d position sufficiently far toward the xe2x80x9copenxe2x80x9d position to result in either leakage of fluid from the coupling, or even separation of the coupling. It is therefore necessary that significant care be exercised when QCD couplings are used. This is not always possible. Several attempts have been made to overcome this difficulty; examples are to be found in Moore, U.S. Pat. No. 3,439,942; Lauffenberger, U.S. Pat. No. 3,976,313; Goodall et all, U.S. Pat. No. 4,295,670; Fahl, U.S. Pat. No. 4,618,171 and U.S. Pat. No. 5,005,876; Vargo, U.S. Pat. No. 4,647,075; and Parrish, U.S. Pat. No. 4,871,195. In these prior patents, three techniques have been used.
The first is to provide a subsidiary locking means which is intended to prevent inadvertent movement of each lever. This comprises a member attached to the coupler that must be deflected in order to move the lever from the xe2x80x9clockedxe2x80x9d position, and is automatically engaged when the lever is moved from the xe2x80x9copenxe2x80x9d to the xe2x80x9clockedxe2x80x9d position. Examples of this approach are Moore U.S. Pat. No. 3,439,942; Lauffenberger, U.S. Pat. No. 3,976,313 and Vargo, U.S. Pat. No. 4,647,075.
The second is to modify the lever itself, so that it is more difficult to move it from the xe2x80x9clockedxe2x80x9d position. Examples of this are Fahl, U.S. Pat. Nos. 4,618,171 and 5,005,876.
The third is to provide an additional positive locking system, which must be separately engaged on each lever, after each lever has been moved to the xe2x80x9clockedxe2x80x9d position, and separately disengaged from each lever before each lever can be moved from the xe2x80x9clockedxe2x80x9d position. Examples of this are Goodall et all, U.S. Pat. No. 4,295,670; and Parrish, U.S. Pat. No. 4,871,195.
These known modified QCD couplings although being less prone to inadvertent lever movement still do not overcome the difficulty. The subsidiary locking means, such as a bent plate, spring wire loop, or spring-loaded ball detent (Moore, Lauffenberger and Vargo) is not difficult to defeat, as also is a modified lever (Fahl). The additional locking systems although far more difficult to defeat, up to a point defeat the xe2x80x9cquickxe2x80x9d attribute of QCD couplings, as each lever has to be separately locked or unlocked each time the coupling is used. Furthermore, these devices require the use of additional small and easily lost items, such a small spring cotterpins (Goodall et all, and Parrish). These devices are thus not easily used by a worker wearing industrial gloves, and once the small item is lost, the subsidiary locking means is useless until it be replaced.
This invention seeks to provide a QCD coupling of this general type, in which a subsidiary locking means is provided which is both positive in its locking action, locks all of the levers simultaneously, and does not involve any small or readily losable parts, as the subsidiary locking means is itself securely attached to the coupler part of the QCD coupling. As an additional benefit, as all of the levers are locked simultaneously, the subsidiary locking means cannot be locked unless all of the levers are in the fully xe2x80x9clockedxe2x80x9d position.
The subsidiary locking means of this invention comprises a cap which is rotatably secured to the coupler body, adjacent to the end of the bore entered by the adapter. The cap can be rotated between an xe2x80x9copenxe2x80x9d and a xe2x80x9cclosedxe2x80x9d position; detent means are provided between the cap and the coupler to retain it in the xe2x80x9cclosedxe2x80x9d position, and preferably also to hold it in the xe2x80x9copenxe2x80x9d position. The skirt of the cap includes slots, which are in registration with the levers, as they are set at the same spacing around the skirt as the levers are set around the coupler body. When the cap is in its xe2x80x9copenxe2x80x9d position, the levers can be moved to their xe2x80x9copenxe2x80x9d positions by entering into the slots in the cap skirt, thus permitting the QCD coupling to be engaged and disengaged as desired. After the levers have been moved to their xe2x80x9cclosedxe2x80x9d position, the cap can be rotated to its xe2x80x9cclosedxe2x80x9d position. It is now impossible to move the levers to their xe2x80x9copenxe2x80x9d position, as the skirt of the cap effectively prevents any substantial movement. The QCD coupling modified according to this invention can only be disengaged when the cap has been rotated to its xe2x80x9copenxe2x80x9d position.
Since the clearance between the cap skirt and the levers when both are in their fully xe2x80x9clockedxe2x80x9d position is minimal, and needs to be only enough to ensure free rotation of the cap, the subsidiary lock of this invention provides the additional safety feature that the QCD coupling cannot be locked unless all of the levers are fully in their xe2x80x9clockedxe2x80x9d positions, which requires that the adapter is also fully engaged into the coupling and urged against the coupler seal.
Thus in its broadest embodiment, this invention seeks to provide a female coupler for a quick connect/disconnect coupling comprising in combination:
a female coupler comprising a body member having a bore for receiving the outer end portion of the male adapter, and a seal constructed and arranged to seal with the sealing surface of the male adapter;
a lever locking mechanism carried by the female coupler comprising a plurality of locking levers pivotally mounted onto the outside of the female coupler, each lever being rotatable between a xe2x80x9cclosedxe2x80x9d position, and an xe2x80x9copen position; a cam member attached to or forming part of each lever extendable on rotation of each lever about its pivot toward its xe2x80x9cclosedxe2x80x9d position through a corresponding slot in the female coupler body into the bore of the female coupler, the cam members being constructed and arranged to engage with a cooperating arcuate groove on a male adapter constructed and arranged to be entered into the bore of the female coupler on rotation of the levers toward their xe2x80x9cclosedxe2x80x9d position;
a cap member rotatably attached to the female coupler adjacent the opening of the bore, the cap member having a skirt which extends along the outside of the female coupling to a point adjacent the lever pivots, and being rotatable on the female coupling between a xe2x80x9cclosedxe2x80x9d position, and an xe2x80x9copenxe2x80x9d position;
a plurality of slots in the skirt of the cap in registration with the levers; and
at least one detent means interposed between the cap and the female coupler constructed and arranged to retain the cap in its xe2x80x9cclosedxe2x80x9d position;
wherein when the cap is in its xe2x80x9copenxe2x80x9d position the levers can be moved into the cap slots to their xe2x80x9copenxe2x80x9d positions, and when all the levers are rotated to their xe2x80x9cclosedxe2x80x9d positions, the cap can be rotated about the female coupling to its xe2x80x9cclosedxe2x80x9d position.
Preferably, the detent means is constructed and arranged to retain the cap in both its xe2x80x9copenxe2x80x9d and its xe2x80x9cclosedxe2x80x9d position.
Preferably, the detent means comprises at least one spring loaded ball carried by the coupler, which enters into a suitably located depression in the cap when the cap is rotated to its xe2x80x9cclosedxe2x80x9d position. More preferably, the detent means comprises at least one spring loaded ball carried by the coupler, which enters into a first suitably located depression in the cap when the cap is rotated to its xe2x80x9cclosedxe2x80x9d position, and into a second suitably located depression when the cap is rotated to its xe2x80x9copenxe2x80x9d position.
Preferably, the cap is rotatably retained on the female coupler by means of a wire inserted into cooperating grooves on the cap and on the coupler body.